Rechallenge with bevacizumab in patients with glioblastoma progressing off therapy

Rechallenge with temozolomide has been shown to be a valid option in selected patients with progressive glioblastoma. Herein, we assessed the efficacy of rechallenge with bevacizumab in glioblastoma patients progressing off therapy. We retrospectively identified and analyzed the characteristics of patients with glioblastoma rechallenged with a bevacizumab-based chemotherapy regimen after having received bevacizumab as first-line treatment in association with temozolomide radiochemotherapy or at recurrence in association with temozolomide, CCNU or irinotecan. Twenty-five patients were identified. In all included patients, the first bevacizumab treatment resulted in an objective response and was discontinued for reasons other than disease progression (adverse event n = 9, physician or patient decision n = 16). Median duration of first bevacizumab treatment was 6 months (range: 2-58 months). None of the patients presented a rebound effect after bevacizumab discontinuation. The median interval between discontinuation of first bevacizumab treatment and bevacizumab rechallenge was 8.9 months (range: 2-58 months). At this time, bevacizumab was given in association with lomustine (n = 17), temozolomide (n = 6), irinotecan (n = 1), or alone (n = 1). Bevacizumab rechallenge resulted in an objective response in 15 patients (60%). Median progression-free survival was 6.7 months and overall survival was 9.6 months after bevacizumab rechallenge. Timing of first bevacizumab treatment (as first-line treatment or at recurrence) was not associated with the duration of response after treatment rechallenge. In the present series, patients who responded to bevacizumab and in whom this treatment was discontinued in the absence of tumor progression seemed to benefit from rechallenge with a bevacizumab-based chemotherapy regimen.